Does anyone know (without speculating) where the infamous
"Operating System Not Found" message comes from?

Is it coming from the BIOS or the early stages of loading the OS (before the splash screen is visible?_________________Free Tibet. Release the Panchen Lama from prison. Let the Dalai Lama return to his home.

It comes from the BIOS, when the BIOS can't find an operating system on any of the assigned boot devices.
Check the boot priority in the BIOS and make sure the drive you want to boot from is recognised and in the queue._________________What makes a space ours, is what we put there, and what we do there.

It comes from the BIOS, when the BIOS can't find an operating system on any of the assigned boot devices.
Check the boot priority in the BIOS and make sure the drive you want to boot from is recognised and in the queue.

Thanks.

This is an intermittent problem. W are trying to understand what the host is doing when it reports that it can't find the OS.

I've also seen "Bootable device not found" on the same machine, but don't understand what makes one message appear over the other.
I've got a bus analyzer connected to the boot drive trying to view the command sequence, but the anaylzer's buffer is being overwritten by low-level signalling information (which we do need to some extent), before we can see the command sequence._________________Free Tibet. Release the Panchen Lama from prison. Let the Dalai Lama return to his home.

Bootable device not found is usually a problem with the chipset not finding a device with the master boot record. When I've seen this in the past, and it was also intermittent, the battery was going on the motherboard. Try resetting your BIOS, and check the battery (if possible). I've seen as the battery goes low, the BIOS settings stored become corrupt. (I never actually had a way to prove that, but new battery + clearing/resetting the bios solved my problem both times).

Bootable device not found is usually a problem with the chipset not finding a device with the master boot record. When I've seen this in the past, and it was also intermittent, the battery was going on the motherboard. Try resetting your BIOS, and check the battery (if possible). I've seen as the battery goes low, the BIOS settings stored become corrupt. (I never actually had a way to prove that, but new battery + clearing/resetting the bios solved my problem both times).

Could one assume "a problem with the chipset not finding a device with the master boot record" would be the cause for "Operating System Not Found" as well?

I suppose if the host can't communicate with the boot drive, all sorts of messages would result, but I'm curious to know how the host differentiates between these situations. I know the boot record is valid, because I can always boot from it if I pwoer cycle the system.

I will see if I can get to the battery. Given that it's a laptop that may not be easy to get to._________________Free Tibet. Release the Panchen Lama from prison. Let the Dalai Lama return to his home.

If this is indeed a laptop, then I'd wager that it is the CMOS battery dying that is the real problem. What kind of laptop is it? Most fairly modern laptops (last 5-6 years anyway) have accessable batteries, either behind a small panel or under the keyboard or something like that._________________Garret: It's so retro.
EGM: What does retro mean to you?
Parker: Like, old and outdated.Home,My Studio,and another view

If this is indeed a laptop, then I'd wager that it is the CMOS battery dying that is the real problem. What kind of laptop is it? Most fairly modern laptops (last 5-6 years anyway) have accessable batteries, either behind a small panel or under the keyboard or something like that.

a Sony Vaiao- it's oinly 2-3 years old, but I'll check the battery anyway_________________Free Tibet. Release the Panchen Lama from prison. Let the Dalai Lama return to his home.

If this is indeed a laptop, then I'd wager that it is the CMOS battery dying that is the real problem. What kind of laptop is it? Most fairly modern laptops (last 5-6 years anyway) have accessable batteries, either behind a small panel or under the keyboard or something like that.

If the laptop is plugged into the power supply, wouldn't the that essentially disconnect (or override) the CMOS battery, until the system was unplugged?

I was under the impression the CMOS setup info only used the CMOS battery when a system was unplugged or in a no power state._________________Free Tibet. Release the Panchen Lama from prison. Let the Dalai Lama return to his home.

If this is indeed a laptop, then I'd wager that it is the CMOS battery dying that is the real problem. What kind of laptop is it? Most fairly modern laptops (last 5-6 years anyway) have accessable batteries, either behind a small panel or under the keyboard or something like that.

If the laptop is plugged into the power supply, wouldn't the that essentially disconnect (or override) the CMOS battery, until the system was unplugged?

I was under the impression the CMOS setup info only used the CMOS battery when a system was unplugged or in a no power state.

My understanding is the battery drains in any case. I've had laptops which died this way (Sony ones, for sure), even with a charged NiMH the CMOS battery went. It should be easy enough to check with a voltmeter, in any case.

Regardless, going into CMOS setup and checking the system clock time, boot order and known devices will tell you if the CMOS is corrupted._________________Garret: It's so retro.
EGM: What does retro mean to you?
Parker: Like, old and outdated.Home,My Studio,and another view

A CMOS battery will go dead in a desktop, with the same results. So, AFAIK, the CMOS backup has nothing to do with whether power is disconnected or not.
Actually, I've never seen anything but Lithium used for CMOS backup, which are not rechargeable either._________________What makes a space ours, is what we put there, and what we do there.

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